High active, selective and sulfur resistant supported palladium tetra-coordinated complex as catalyst in the selective hydrogenation of styrene

The [PdCl2(CH3SOCH3)(2)] complex supported on gamma-Al2O3 was studied as catalyst in the selective hydrogenation of styrene to ethylbenzene. This catalyst is considerably more active, selective and sulfur-resistant than a conventional catalyst obtained from an acid solution of PdCl2. As determined by XPS and IR, the active species is the complex itself, which is stable under the reaction conditions. The complex is destroyed, at least partially, by hydrogen treatments above 353 K, leading to a less active and less sulfur resistant catalyst. The highest sulfur resistance can be attributed to electronic and geometrical effects.